Surface features of cirrhotic liver.

The surface features of single cells and of multicellular tissue units in cirrhotic rat livers have been studied by scanning electron microscopy (SEM). Cirrhosis of the liver was produced in rats by simultaneously treating them with carbon tetrachloride and sodium phenobarbital. Connective tissue septa consisted of a losse mesh-work of fibers in which fibroblasts were embedded. The arrangement and surface features of hepatocytes in cirrhotic nodules differed from those found in parenchyma of normal livers. Hepatocytes in cirrhotic nodules universally formed plates two cells thick. The portion of the hepatocyte surface covered by microvilli was greatly increased in cells from cirrhotic livers, and this was reflected in a corresponding reduction in the area occupied by the smooth-surfaced narrow intercellular space. Canaliculi between hepatocytes in cirrhotic livers were reduplicated and frequently branched. hepatocyte surfaces covered by microplicae and flattened microvilli, typical of connective tissue-facing surfaces in normal livers, were greatly increased in cirrhotic livers corresponding to the increase in connective tissue. Where hepatocytes directly contacted fibroblasts (and not fibers), their surfaces were entirely smooth. Sinusoidal endothelial cells in cirrhotic livers contained only isolated, relatively sparse pores, and they lacked both sieve plates (pore complexes) and large fenestrations.